The invention is based on a fuel injection system as generally defined hereinafter. At higher altitudes, because of the lower air density, the aspirated air mass is smaller. The full-load quantity that is injected cannot be combusted completely, causing smoke to develop and the engine temperature to rise. In order to prevent this, an injection system of the above general type is known from European Patent A No. 0012309 (FIG. 1), having a full-load stop that is dependent on atmospheric pressure and that varies the full-load quantity in accordance with the air pressure. In this injection system, the control stroke of the air pressure control member is converted and transmitted via a conical cam connected to the adjusting rod of the adjusting member and via a scanning pin that is displaceable transversely with respect to this cam. The air pressure adjusting member, which comprises a plurality of barometer boxes, has a relatively low working capacity if its dimensions are small, which is possible when the member is used in combination with an injection system.